An organic light-emitting diode (OLED) display, compared to a liquid crystal display (LCD), has advantages of self-illumination, quick response, wide angle of view, high brightness, bright color, light weight and small thickness, and the like, and is considered to be the next generation display technology.
Modes for realizing colorization of OLED mainly include: R/G/B side by side mode, R/G/B/W square mode and white OLED in combination with color filter (WOLED+CF) mode.
WOLED+CF mode is considered to be the main mode used in mass production of large-sized OLEDs. Currently, white OLEDs are mainly manufactured through an open mask process or a solution process.
FIG. 1 is a schematic diagram of an OLED manufactured through an open mask process in the prior art. As shown in FIG. 1, the OLED manufactured through the open mask process comprises: a substrate 1, pixel define layers (PDLs) 2 formed on the substrate 1, first electrodes 4 formed between adjacent pixel define layers 2, an organic layer 5 formed on the first electrodes 4 and a second electrode 6 formed on the organic layer 5. The OLED comprises a plurality of PDLs 2 which define sub-pixel units 3, in each of which one first electrode 4 is included. The organic layer 5, as a whole, is formed by evaporation with an evaporation mask, and is one layer of thin film. However, the organic layer 5 is formed not only on the first electrodes 4 but also on the PDLs 2, and protrusions of the PDLs 2 with respect to the first electrodes 4 may cause portions of the organic layer 5 corresponding to edges of the first electrodes 4 to be uneven, which may result in relatively poor flatness of the formed film of the organic layer 5 on each first electrode 4. Also, since a condition that portions of the organic layer 5 on different first electrodes 4 have different thicknesses may occur in the evaporation process, the formed film of the organic layer 5 has a poor uniformity. If the uniformity is badly poor, a short circuit may even occur, and therefore, display quality of the OLED is severely influenced.
FIG. 2 is a schematic diagram of an OLED manufactured through a solution process in the prior art. As shown in FIG. 2, the OLED manufactured through the solution process comprises: a substrate 1, PDLs 2 formed on the substrate 1, first electrodes 4 formed between adjacent pixel define layers 2, an organic layer 5 formed on the first electrodes 4 and a second electrode 6 formed on the organic layer 5. The OLED comprises a plurality of PDLs 2 which define sub-pixel units 3, in each of which one first electrode 4 is included. The organic layer 5 is formed in each sub-pixel unit through the solution process, and in this case, edge portions of the organic layer 5 contacting with the PDLs 2 may form upward protrusions (i.e., coffee-ring phenomenon), which may result in relatively poor flatness of the formed film of each organic layer 5. Also, since a condition that portions of the organic layer 5 on different first electrodes 4 have different thicknesses may occur in the solution process, the formed film of the organic layer 5 has a poor uniformity, and thus display quality of the OLED is severely influenced.